Trust, but verify

B3 Spirit

The youngest active stealth bomber in the U.S. turns 15 this year,
and the other 19 B-2s in the Air Force fleet are nearly five years
older. Meanwhile, the integrated defense systems they face have become
much more sophisticated. Multi-static radar, which is now relatively
common, is so sensitive that it can detect certain stealth craft. To
stay ahead of such defense systems, the Air Force has budgeted $3.7
billion over the next five years to develop a successor to the B-2 that
could be active by 2020. Actual designs of the new bomber are
classified, but some secrets are already out.

Patents and bid proposals from Northrop Grumman, maker of the B-2,
suggest that the new bomber will be narrower than the B-2 but maintain
the familiar flying wing design, which reduces radar reflection by
minimizing hard edges. Engineers are also testing new types of
radar-absorbing coatings that could be customized to individual defense
systems. And so a picture of the next generation of stealth bombers is
beginning to emerge.

CUSTOM COATINGS

Most stealth coatings consist of a radar-absorbing material, typically a form of iron,
suspended in paint. But they are heavy (which lowers fuel efficiency),
need to be reapplied frequently, and don’t absorb all radar frequencies.
Ceno Technologies, a particles-science company in Sanborn, New York,
has developed a lighter, more durable coating that uses hollow ceramic
spheres, called cenospheres. Because the spheres can be covered in
carbon, silver or other metals that absorb slightly different
wavelengths of radar, the coating can be customized to deceive specific
radar systems.

SMOOTHER SHAPE

The B-2 has two semi-flush air-intake vents, the hard edges of which
can reflect radar. In one design seen in a patent from Northrop Grumman,
the new bomber has four small vents rather than two large ones. The
smaller vents can be buried more deeply in the wing, reducing the
possibility of radar returns.

SMARTER DECOYS

To confuse radar defense systems, the new bomber will probably carry
something like the Miniature Air Launched Decoy made by Raytheon. The
modified drones use radar reflectors to create bomber-like signatures
that divert attention from the actual bomber. The decoys fly on a
preprogrammed course for up to 575 miles and may carry radar jammers to
further confuse air defenses.

RETRACTABLE WING

In one design from Northrop Grumman, engineers included a canard wing
on the plane’s nose, which would provide extra lift during takeoff and
flight, allowing a smaller bomber to carry a heavier weapons payload.
Because its straight lines and hard angles would reflect radar, the
canard wing will most likely be designed to fold flush with the bomber’s
body as the craft comes within range of defense systems.

HEAVIER WEAPONS

The new bomber will most likely have a single weapons bay, as opposed
to the twin bays on the B-2. It will still be able to carry
conventional GPS-guided JDAM missiles, nuclear warheads and even the new
30,000-pound, bunker-busting Massive Ordnance Penetrator, but a single
bay would reduce the cost of manufacturing—a major concern for designers
on a relatively tight budget.